FREQUENCY-RESPONSE ANALYSIS OF CANADIAN LOGGING TRUCKS

This paper examines the frequency responses of ten logging truck configurations currently operating in the interior of British Columbia in Canada. The work is an extension of a previous study conducted at the National Research Council (NRC) in 1990. The previous study presented an extensive analysis of the directional responses and frequency responses of four Canadian log-hauling truck configurations; a tractor/pole trailer, a tractor/triaxle trailer, a tractor/quadaxle trailer (with a single load), and a tractor/single-axle-jeep/pole trailer. In the current study, the frequency responses of these four configurations are compared with those of six more log-hauling truck configurations; a tractor/tandem-axle-jeep/pole trailer, a doglogger, a double doglogger, a tractor/quadaxle trailer (with a dual load), a tractor/jeep/triaxle trailer, and a tractor/jeep/quadaxle trailer. The current study makes use of three models developed by NRC in the previous study, and a new model developed at NRC in cooperation with the University of Victoria. The frequency response method has been applied in this study to predict the lateral acceleration at the centre of gravity of each articulated vehicle unit, and the rearward amplification ratio. The logging truck simulation results have been compared with corresponding results, obtained using UMTRI's simplified models, for three conventional highway vehicles; a tractor/semitrailer, a B-train, and an A-train. The comparison provides a useful indication of the differences between the behaviours of logging trucks and conventional highway trucks in their shared environment.